1. Field of the Invention
The present invention relates to a novel zoom lens and an imaging apparatus. More specifically, the present invention relates to an image-shiftable zoom lens which may shift image by shifting a part of lenses in directions approximately perpendicular to an optical axis, as well as to an imaging apparatus equipped with the zoom lens.
2. Description of Related Arts
As a recording mean of a camera, there has been known a method in which recording of a subject image formed on an imaging device plane is performed after conversion of a light intensity of the subject image into electric output with each photoelectric converting element by an imaging device using of photoelectric converting elements, such as Charge Coupled Devices (CCDS) and Complementary Metal-Oxide Semiconductors (CMOSs).
In recent years, as the number of photoelectric converting element pixels increases, an angle of view with respect to one pixel size becomes narrow, and an image blur is caused by a camera shake and others when shutter release is made. Consequently, there tends to be a marked problem that an image is recorded at an unclear state.
Further, a highly integrated circuit substrate included in a camera allows a camera body to be smaller in size and lighter, and as more cameras are provided with a large-sized liquid crystal display, a camera body is kept apart from a user's body in order to view a liquid crystal display during the image taking. Due to the above and other reasons, users have, more frequently than ever, a higher chance to take images in a condition where the camera body is susceptible to shakes. Thus, the image blur caused by the camera shake becomes a serious issue.
Optical camera-shake correcting systems are known as a camera-shake correcting system for correcting the image blur caused by the camera shake and others.
As one optical camera-shake correcting system, there is a lens shift scheme in which a part of the lens system is shifted in directions perpendicular to an optical axis. Optical systems disclosed in Japanese Patent Application Publication No. JP Hei 1-116619 (Patent Document 1), Japanese Patent Application Publication No. JP Hei 6-337374 (Patent Document 2), Japanese Patent Application Publication No. JP Hei 11-174329 (Patent Documents 3), and the like are known as an optical system employing the lens shift scheme of this type, for instance.
A zoom lens presented in Patent Document 1 includes three lens groups, in order from the object side, a first lens group having a negative refractive power, a second lens group having a positive refractive power and a third lens group having a negative refractive power, in which image shift is provided by shifting the second lens group in directions approximately perpendicular to an optical axis.
A zoom lens presented in Patent Document 2 includes two lens groups in order from the object side, a first lens group having a negative refractive power and a second lens group having a positive refractive power, in which image shift is provided by shifting the second lens group in directions approximately perpendicular to an optical axis.
A zoom lens presented in Patent Document 3 includes four lens groups in order from the object side, a first lens group having a negative refractive power, a second lens group having a positive refractive power, a third lens group having a negative refractive power and a fourth lens group having a positive refractive power, in which image shift is provided by shifting the third lens group in directions approximately perpendicular to an optical axis.